I have two iPads that will not let me sync over wi-fi. I've followed the directions and clicked the box for "sync this iPad over Wi-Fi" and hit the apply button. However, when trying to sync over wi-fi, I still get the message: "To enable Wi-Fi syncing with iTunes, connection to iTunes on your computer using a cable and click "Synch with this iPad over Wi-Fi." I've tried unclicking the box and applying, then clicking again and applying but nothing changes. I have no problems syncing over wifi with my newest iPad or my iPhone 7Plus.
How can I fix this issue?